Animal models are used for the evaluation of the safety and immunogenicity of acellular pertussis vaccines before administration to humans. The aerosol challenge model provides a reproducible system for the study of virulence factors and immunity involved in respiratory infection and subsequent disease. Clinical studies have shown that acellular pertussis antigens are protective against disease; however, to date, there is no serum antibody concentration that has been shown to correlate with vaccine mediated protection. In some recent publications, authors have suggested that when mice were immunized with whole-cell and acellular vaccines and then challenged with an aerosol of B. pertussis, the clearance of infection from the lungs paralleled the ability of these vaccines to protect children against pertussis. Using our mouse aerosol challenge model, we are attempting to reproduce these results with pertussis containing vaccines of known low and high clinical efficacy, If the observations can be verified, the model could be used to evaluate changes in manufacturing of new combination vaccines. Additionally, the model could be used to determine whether an immunization schedule that includes vaccines from more than one manufacturer is as efficacious as a schedule that uses vaccine from a single manufacturer.